Clam shell door construction



1956 s. F. ARMING'TON 2,729,503

CLAM SHELL DOOR CONSTRUCTION Filed Aug. 11, 1951 2 Sheets-Sheet l INVENTOR.

JTEWART f. ARM/warm ATTORNEYS Jan. 3, 1956 s. F. ARMINGTON 2,729,503

CLAM SHELL DOOR CONSTRUCTION Filed Aug. 11, 1951 2 Sheets-Sheet 2 INVENTOR.

JTEWART E ARM/NGTON ATTORNEYS United States Patent 2,729,501 CLAM SHELL noon CONSTRUCTlON Application August 11, 1951, Serial No. 241,431

12 Claims. ct. ass-35 This invention relates to improvements yin bottom dumping wagons or hoppers and more particularly to the novel bottom door construction thereof.

This application discloses the same subject matter as the copending application of Harvey L. Rittenhouse for Exhaust Heating Semi-Trailer Bodies, Serial No. 226,687 filed May 16, 1951. T1

One of the objects of the present invention i s,to provide in a bottom dump wagon, or hopper of the type described, means to provide freer dumping of the load, a lower center of gravity, and a smaller clearance between the ground and the bottom of the wagon or hopper.

Another object of the present invention is to provide in a bottom dump wagon or hopper of the type described bottom dump doors supported, opened and closed by means intermediate the end walls of the wagon or hopper.

Another object of the present inventionis ito provide in a bottom dump wagon or hopper of the type described hydraulically actuated bottom dump doors instead of cable actuated doors. The cables of the conventional cable actuated doors have a short life and ahigh maintenance cost.

Another object of the present invention is to provide in a bottom dump wagon or hopper of the type described bottom dump doors supportedby brackets. protruding through slots in the wagon or hopper side walls so that the hopper rigidity is not diminished.

Another object of the present invention is to provide in a bottom dump wagon or hopper of the type described at least one bottom dump door having a pivoted scraper plate thereon adapted to have a constant scraper angle with the load supporting surface of the door while the door is being opened. When the door is nearly open, the scraper plate is adapted to fall to a substantially vertical position so that it will not interfere with thedumping of the load.

Other features of this invention reside in the arrangement and design of the parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and, descrip tion and the essential features thereof will be set forth in the appended claims.

In the drawings,

Fig. 1 is a side view of the, bottom dumping wagon; or hopper of this invention;

Fig. 2 is a top view of a portion of the wagon or hopper shown in Fig. l;

Fig. 3 is an enlarged sectional view along the line 3-3 of Fig. 1 and showing the mechanism to support, open and close the bottom dump doors of the bottom dump wagon or hopper of this invention with the doors in their closed position in solid line and in their open position in dot-dash line; while Pig. 4 is an enlarged sectional view taken along the. line 4-4 of Fig. l and showing the pivoted scraper plate engaging the load supporting top surface or one of the closed bottom dump doors; and

pivotally mounted at 21 on each end wall.

2,729,503 Patented Jan. 3, 1956 Fig. 5 is a view similar to Fig. 4 but shows the door in its open position.

Figs. 1 and 2 disclose the bottom dump trailer or hopper, generally indicated at 10, as being pivotally hitched to a tractor, generally indicated at 11. Rear wheels 12 of the trailer carry the back portion of the trailer load while wheels 13 of the tractor support the front of the trailer. Fig. 1 also discloses the flexible connection between the exhaust of the tractor and the hollow ribs of the trailer so that the trailer walls may be heated in freezing weather to facilitate dumping. The structure for heating the trailer walls is fully disclosed in the copending application of Harvey L. Rittenhouse on Exhaust Heating Semi- Trailer Bodies, Serial No. 226,687 filed May 16, 1951.

The invention in this application relates to the novel bottom dump door construction and is described in further detail hereinafter.

The bottom dump trailer or hopper 1G is of welded construction. It consists of two opposite side walls 14 and two opposite end walls 15. Opposite side walls converge downwardly as seen in Figs. 2 and 3. Each side wall has a longitudinally extending rigid frame member along its top edge, as seen at 16, and another rigid frame member 17 extending along its bottom edge. A slot 18 is formed in the mid-portion of each side wall between the two longitudinally extending frame members 16 and 17. A hollow transverse housing 19 within the hopper is rigidly connected to the side walls so as to stiffen the hopper, to keep them spaced a constant distance apart and also to protect the door actuating and supporting means shown in Fig. 3. The hollow ends of housing 19 register with slots 18.

The dump trailer or hopper 10 has a novel bottom dump door construction. Two bottom dump, clam shell doors 20 cover the bottom of the hopper or trailer and extend generally parallel to the side walls. Since the two doors 20 and the supporting, opening and closing mechanism for each are identical, only one door and associated mechanism will be described. Each door is Intermediate the end walls a C-shaped bracket 22 is attached to door 20. This bracket rigidly extends through the slot 18 in the adjacent side wall to support the bottom dump door 20 outside and below the hopper. The c-shaped bracket is pivotally mounted at 23 within and secured to the transverse housing 19 of the hopper. Note that this pivot point 23 is at a point that is less than half of the door width from the center of the dump trailer or hopper so that the door will close by gravity, if desired. in other words, the center of gravity of a door is always laterally outside of a vertical plane through its supporting pivot. Usually, the bottom dump door is only supported at its ends so that the hopper side wall is not weakened. However, with this construction having slot 18 and C-shaped bracket 22, the door 20 may be supported intermediate its ends also, thus providing a stronger construction. With this intermediate support, the door will be stronger. If the door is of equal strength, it can be made of lighter material. The intermediate support also makes the door easier to open. The door will have less tendency to buckle under load and the load will be better distributed with an intermediate door support than with only end door supports. The lower longitudinally extending frame member 17 does not have to be out since the C-shaped bracket 22 extends through slot 18 in the side wall and around member 17. The longitudinally extending frame member 17 extends on to the rear of the wagon and sup ports the dump trailer body on the rear wheels 12. Since the frame members 16 and 17 are continuous and uninterrupted they can perform their normal function of strength ening and making rigid the side wall of the bottom dump trailer. The supporting and actuating of the door 20 by C-shaped bracket 22 intermediate the end walls 15 between the distal edge of g the 'grod'iid;""'Thi's' makes'it' necessary to maintain at does not weaken the major framework of the attenuate? or hopper. However, this invention contemplates and includes a bottom dump door without this pivotal mounting on the end walls where this mounting is not needed since the door is mounted intermediate its ends. Y

Means is also provided to open and close the doors 20. Since the mechanism to open and close each door is identical, the mechanism for controlling only one door will be described. A double acting hydraulic jack i ldis located within the transverse housing 1% in the hopper. With the double acting feature, the hydraulic jack is adapted to both open and close the door by hydraulic pressure. Of course, this invention contemplates that the jack could be single acting. Then, the hydraulic pressure would only open the door; the door would close by gravity. The hydraulic jack 24 is pivoted to the hopper at 25 and to the C-shaped bracket 26. The hydraulic jack 24 consists of three telescoping cylinders 24b, and 24c. Cylinder 24c may be a solid cylinder or piston rod and need not be hollow like the otter two cylinders. This construction permits the door Zii to be moved more slowly during the first part of its opening movement when the load within the trailer or hopper ofi'ers the greatest resistance and the most power is needed tomove the door. This construction also permits the door to be moved more rapidly during the final part of its opening move ment than during the first part of the opening move ment. Hence, this, construction gives a rapid but sure door opening and load dumping. v

A means is provided to cause, the doors to move in synchronization. This means consists oi gear segments 27, one attached to each C-shaped' bracket 2'22 concentric with pivot 23. With these gear segments, each door will be opened the same amount at the same time and wil move synchronously. i

Although the bottom dump trailer is complete, as described above, a scraper plate may be added for each door, as shown in Fig. 3, if desired. Since both scraper plates are identical, only one will be described. Fig.4 discloses an enlarged View of the hinged, door scraper plate 28 pivoted on the lower edge or" a side wall 1 of the bottom dump trailer or hopper. he scraper plate 28 is adapted to engage the top load supportingsurface 29 of the door 29 to scrape the surface free of the dirt or rock in the loadas the door opens. The weight of the scraper plate and the weight of the load on top of it keeps it constantly engaged with the top surface 29 while the door is being opened. The major portion of the top surface 29 consists'of a curve Sli of substaruially l constant radius. This radius has its center at the pivotal axis 23 of the door. While the plate travels over'this curve 30, a constant and etlicient scraper angle ismain tained. The parts shown in 4 are so arranged that the optimum scraper angle-is obtained At the dis'tal edge of the door 28, a top surface 31 extends tangentially to the curve 3%). When plate engages this surface, as the door is being opened, the plate re. H ii are substantially vertical position, as seen i v 5. Hence, when the door is open the scraper plate does not obstruct the downward flow of material from the dump trailer or hopper 10. Although the scra or plate Ztlis hown as being applied to both doors in Fig. 3, it can be i only one door if desired." v

This construction has many advantages over th'e c nventional bottom dump trailer now used. The -present bottom dump trailer sometimes does n otdun'lp'itsload. This is a result of the downwardly tapered sides andends of the hopper body. Rocky materials-and frozen chunks or sticky clay materials wedge into these tapers and bridge across the trailer or hopper body so that'jthe load may not dump completely. Also, with the present type 'ofibot tom dump doors, it is necessary thatthe bddyofthe straighter sides to provide freer dumping.

the door in the open position least three and one-third foot clearance under the body of the conventional bottom dump trailer at its lowest point. if the downward taper of the walls is reduced to keep material from wedging in the trailer, the body of the trailer or hopper must be widened to have the same load capacity. Then, wider doors are required. Thus, the ground clearance must be made still larger. A larger ground clearance- 'resultsi-in an undesirable design having a'high center of gravity "and a high loading height; The door construction of this invention permits a hopper with It permits a 4 hopper with a lower center of gravity. It is possible with this new construction todesign the hopper so that the bottom has a clearance of 22 inches instead of inches, as required heretofore for a similar sized hopper of bottom dump type.

Note that the front end of the bottom dump trailer or hopper is lower than the rear end. This gives larger wagon capacity at the forward end of the trailer or hopper and also'places more load on the tractor drive wheels.

The hydraulic jacks 24 to away with the conventional cables used to actuate the bottom dump doors of this type of bottom dump trailer. On the conventional trailer, the cable is usually dragged through the load, and the rocks and other abrasive material in the load soon wear out the cable.' 'This 'gives the cables a short wear life and results I torn dump hopper, said hopper having side walls, a longitudinally, extending frame member at the bottom of each sidewall, leach sidev wall having a slot therein above the frame member,- two bottom dump doors with one door corresponding to eachs'id'e: walkeach door swingable outwardly ahd inwardly under its corresponding frame member and side walls, twobrackets, each supporting a door and beifnglpivo'tally mounted within the hopper intermediate thesidefwalls and ends of said hopper, each bracket extending from its pivot point through one of said slots around the outside of one of said frame members to support its door outside and below the hopper, and the inner edges ot said doors meeting in their closed position below the hopper between the vertical projection of said frame members.

"2.'"" 'A dumping wagon, comprising a transportable bottom dump hopper, said hopper having side and end Walls with an opedbottoin, a longitudinally extending frame member at the bottom of each side wall, each side wall havin a 'slot 'cut'therih located wholly above the frame member, two bottom dump doors for opening and closing said 0'p'en, bottom, each'door being arcuate in shape and pivotally m'oiinted'at the center of curvature of said arcuate shape to atleast one of said end walls, two brackets, each supporting'a'door and being pivotally mounted within the hopper intermediate the sideand end walls of said hopper,

- and close said dqorsso that said doors when open are trailer or hopper be high enough in the air so that the displaced" laterally outwardly from said open bottom and do notimpede bottom dump flow,

3. A dumping wagon, comprising a transportable bottom dump hopper, said, hopper having side walls and ends, a longitudinallyextending frame member at the bottom of each sidewall, each sidewall having a slot therein above the frame member, two bottom dump doors with one door corresponding to each sidewall two C Shaped brackets, each's'uppo "it; a door'andbeihg pivotally mounted with ini t'he hopperfintermediate'the sidewalls and ends of said hoppen'eacli C shape'd bracket extendingthrough one of said slots around and outside of the corresponding frame member to support its door outside and below the hopper for oscillating said door below and outside its corresponding frame member, and means to open and close said doors.

4. A dumping wagon, comprising a transportable bottom dump hopper, said hopper having side and end walls, a longitudinally extending frame member at the bottom of each side wall, each side wall having a slot cut therein above the frame member, two bottom dump doors extending generally parallel to said side walls, each door being pivotally mounted to at least one of said end walls, two C-shaped brackets, each supporting a door and being pivotally mounted within the hopper intermediate the side and end walls of said hopper, each C-shaped bracket extending through one of said slots and around the outside of one of said frame members to support its door outside and below the hopper, two hydraulic jacks located within said hopper, each attached to said hopper and one of said C-shaped arms, each of said jacks consisting of a plurality of telescoping cylinders, and a housing within said hopper to cover and protect the C-shaped brackets and cylinders, said housing rigidly connected to said side walls to stiffen said hopper, the top surface of each door forming a curve of substantially constant radius from the pivotal axis of said door, two scraper plates, each pivoted on the lower edge of one of said side walls and engaging said top surface of its associated door so that a constant scraperangle is maintained, the inner edge of each door having said top surface tangential to said curve so that said scraper plates will rapidly fall to a substantially vertical position when said doors are opened. 1

5. A dumping wagon, as set forth in claim 2, wherein the center of gravity of each door is laterally outside of a vertical plane through the pivot on its supporting bracket so that the doors will close by gravity.

6. A dumping wagon, as set forth in claim 1, said doors being swingable inwardly to said closed position and outwardly to an open position, and means locating the cen' ter of curvature of each door and the pivotal mounting of each door so that the doors do not move below sub- 6 stantially the level of their closed position when moving between closed and open positions and so that minimum ground clearance is required under said dumping wagon.

7. A dumping wagon, as set forth in claim 1, wherein the inner edge of each door is located approximately ver tically below its associated frame member when said doors are in open position so as not to impede the downward dumping flow.

8. A dumping wagon, as set forth in claim 1, wherein the bottom of each slot is above its associated frame member.

9. A dumping wagon, as set forth in claim 1, wherein each slot in a side wall has closed ends.

10. A dumping Wagon, as set forth in claim 1, wherein each door has an approximately constant radius of curvature centered at its pivot.

11. A dumping wagon, as set forth in claim 10, wherein the pivot of each door is located approximately above the path of movement of its inner edge so that said doors swing laterally outwardly in moving from the closed to the open position.

12. A dump wagon, as set forth in claim 1, wherein each door has an approximately constant radius of curvature centered at its pivot and its pivot is located approximately vertically above the lowest point of said curvature so that said doors in moving from said closed to open position swing laterally outwardly.

References Cited in the file of this patent UNITED STATES PATENTS 1,752,056 Armington et a1. Mar. 25, 1930 2,231,545 Myers Feb. 11, 1941 2,246,354 Garlinghouse June 17, 1941 2,268,290 Landis Dec. 30, 1941 2,316,412 French Apr. 13, 1943 2,339,039 Wood Jan. 11, 1944 2,401,407 Benbow et a1 June 4, 1946 2,494,472 DeSaussure Jan. 10, 1950 

